Reliability of spontaneous electrodermal activity in the cat as a function of waking and sleep stages

This study was designed to examine the reliability of spontaneous electrodermal activity (EDA) as a function of the stages of sleep and waking in freely moving cats. Five adult cats were observed during waking--sleep sessions. The results show that: (a) for all stages, the reliability of EDA is slightly higher for amplitude of SSPRs than for frequency; (b) during drowsiness, a maximum of reliability is observed, as is a slight decrease during slow wave sleep; during paradoxical sleep, reliability decreases greatly to below that of the waking level; (c) the reliability of spontaneous EDA appears to be higher in waking cats than that quoted for human subjects. These results are discussed with reference to individual characteristics and state variables.